Alphanumeric printing system employing liquid crystal matrix

ABSTRACT

A completely solid state printing system having a keyboard or computer input, a bit encoder or data translator, a matrix switching system, a liquid crystal matrix to optically form the characters to be printed, a fiber optics translator, and a xerographic printing machine to reproduce the character impressions received from the fiber optics translator.

are 39829960 5 f ,i 1 f (5?; Unite Statr 1111 3,824,604 Stein 1 July 16,1974 [54] ALPHANIUMERIC PRINTING SYSTEM 3,693,517 9/1972 Clark 95/45 R3,716,290 2/1973 Borel et a1. 350/160 LC EMPLOYING LIQUID CRYSTAL MATRIX[76] Inventor: figt g' g 5' Primary Examiner-Samuel S. MatthewsAssistant ExaminerRichard A. Wintercorn [22] Filed: Oct. 12, 1972Attorney, Agent, or Firm-Strauch, Nolan, Neale, Nies 1211 Appl. N()..'297,011 Km v 5 [52] U.S. Cl. 354/5, 350/160 LC, 355/40 7] ABSTiRAFT 5 1]1m Cl. 34% 13 09 34 15 1341b 17/00 A completely solid state print ngsystem having a key- [581 Field Search 355/40; /45; board 91 Computer P@"COdm data 350/16() LC Iator, a matrix switching system, a liquidcrystal matrix to optically form the characters to be printed, 21 fiber5 References Cited optics translator, and a xerographic printing machineUNITED STATES PATENTS to reproduce the character impressions receivedfrom I the fiber optics translator. 3,499,112 3/1970 Heilmeier et a],350/ LC 3,626,830 12 1971 Sobottka et a1 95/45 R 15 Claims, 6 DrawingFigures 10 INPUT ENCODER I4 RING COUNTER IIIIIIIIIIIIIIII LIQUID CRYSTAL-/I8 MATRIX FIBER OPTICS OPTICAL INPUT PRINTER 22 3 824004" GRIN 359PAIENIED 51974 3.824.604 SHEET 1 (IF 3 IO INPUT I2 ENCODER l4 RINGCOUNTER IIIIIIIIIIIIIIII l LIQUID CRYSTAL A/Ie MATRIX FIBER OPTICSOPTICAL INPUT PRINTER FIG. I

ALPI-IANUMERIC PRINTING SYSTEM EMPLOYING LIQUID CRYSTAL TX BACKGROUND OFTHE INVENTION A basic solid state printing system employing a memorybank output, matrix encoding means alphanumeric character forming means,and a printout means opera- The general system under discussion isclearly disclosed in three prior U.S. pats. Nos. 3,217,640 issued toBradshaw; 3,354,817 issued to Sakurai et al. and 3,453,648, issued toStegenga. In each case, however, mechanics enter in along the the systemimparting unreliability of performance. An easily recognized example ofthis is found in the disclosure of the U.S. pat. No. 2,632,386 toHyland, wherein a wire type print machine uses alphanumeric characterblocks as the actual print means, each block having 35 extensible printbits to form the individual character. If one'or more bits jam in highspeed operation, which they invariably will, then the entire printingsystem is imperfect.

In major contradistinction to prior art systems and processes, thepresent invention calls for an optical character matrix system tooptically form the characters and convey the same to optical inputprinting means, such as a xerographic machine.

SUMMARY OF THE INVENTION It is the primary object of the invention toprovide an alphanumeric character printing system having a lightopticalcharacter forming and conveying means to the printing means.

It is another object of the invention to provide such a printing systemwith a liquid crystal matrix to form an individual, light-opticallyreadable character.

Yet another object of the invention is to provide such a printing systemwith a liquid crystal matrix to form one or more lines oflight-optically read characters for differential character spacingresulting in even line printout.

A further object of the invention is to provide such a printing systemwith a two-stage alphanumeric character forming matrix, using a circulareasily formed etched surface electrode to translate data into opticallyreadable bits and a fiber optics system to convey the readable bits toan alphanumeric character display board.

A still further object of the invention is to provide such a printingsystem with either a steady or intermittently actuated light source toconvey the formed alphanumeric character from the character display tothe optical input printing means.

Further novel features and other objects of this invention will becomeapparent from the following detailed description, discussion and theappended claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS Preferred structural embodiments of thisinvention are disclosed in the accompanying drawings in which:

FIG. 1 is a block diagram outlining the entire printing system andprocess;

FIG. 2 is a diagrammatic view of one embodiment of the alphanumericcharacter forming means, employing a liquid crystal matrix for eachcharacter;

FIG. 3 is a partial plan view showing a line matrix instead of thesingle character matrix of FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing a twostage alphanumericcharacter forming system employing a circular liquid crystal matrix;

FIG. 5 is a partial sectional view of the liquid crystal matrixillustrated in FIG. 4; and

FIG. 6 is a partial plan view showing a multiple adjacent line matrixfor forming graphic images.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The schematic block diagram ofFIG. 1 clearly illustrates the entire printing system of the instantinvention. Input 10 may be either a keyboard or computer input fortranslating the data which is to eventually be retranslated and printed.In easily understood lan guage, input If) is a properly programmedcomputer which in and of itself forms no part of the instant invention.Data from input 10 is then conveyed to a matrix bit encoder 12 whichperforms itsusual function of transforming raw input data into propersequence to be eventually fed to the alphanumericcharacter forming meansand'printout. Next, a ring counter 14 may be used to switch fromalphanumeric character matrix to alphanumeric character matrix (e.g.,FIG. 2) or, in another embodiment, the bit encoder 12 may be arranged toprogram an entire alphanumeric character matrix line (FIG. 3) for moreacceptable, differential character spacing for even line printout.

Liquid crystal matrix M forms characters via a common electrode andmultiple input electrodes which change each liquid crystal input bitfrom opaque to clear to form a complete character, as will be furtherexplained below. Alternatively, the specific liquid crystal used mayturn from clear to opaque when receiving an impulse; both types ofliquid crystals are currently commercially available. Through fiberoptics l8 arranged to one side of the matrix 16 and a steady orintermittent light source 20 on the other (FIG. 2) the alphanumericcharacter is conveyed to an optical input printer 22 which, in apreferred embodiment, comprises a xerographic machine 24 (FIG. 2).

As shown in FIG. 2 and at the right side of FIG. 4, the liquid crystalmatrix 16 comprises an alphanumeric character block comprising sevenrows of five liquid crystal bits each, or a total of 35 data input,binary (off-on) bits 26 to form the desired alphanumeric character. Thisarrangement of bits to comprise an alphanumeric character display isclassic, described in the prior art discussed above, and is clearlyshown in the Hyland U.S. pat., No. 2,632,386.

As llereinbefore set forth, computer It), encoder l2 and ring counter ormatrix switcher 14 operate in the usual manner; a bundle of 35 inputlines 28 electronically conveys the translated input data to the liquidcrystal matrix 16, one input line being provided for each liquid crystalbit 26 (FIG. 2). By way of example, suppose it was desired to displaythe letter I on the single matrix 26. Such a single matrix is also shownin FIG. 4, numbered 30. Each bit 32 of matrix 30 is numbered left toright by successive rows from ii to 35. To form the letter I, the bits32 numbered 2, i, 32, 3d, and the central vertical column numbered 3, 8,13, T10, 23, 28 and 33 would be activated to display the letter I."Similarly in FIG. 2, the central vertical column of bits 26 would becharged along with the bits to either side of the vertical column at topand bottom to display the letter I."

Unlike prior art devices, display and transfer of alphanumericcharacters on the matrix 16 and transfer of the characters to printoutmeans is entirely optico-- electronically actuated to completelyeliminate any need for mechanical devices and thus impart a high degreeof stability and reliability to the entire printing system.

Specifically, each alphanumeric bit 26 comprises a liquid crystal, acholesteric compound having significant electrooptical properties. Thesecholesteric compounds are marketed by Eastman Kodak Company ofRochester, New York, and are described and listed in detail in EastmansLiquid Crystals Kodak Publication No. 1]14. The compounds are of smecticand nematic varieties, the nematic one being the type possessingelectro-optical properties.

By way of background, liquid crystals are incomplete or semicrystallinestructures having two distinct mesomorphic states, the first beingnematic, wherein the orientation of molecules or atoms making up thecrystal are arranged in parallel lines but not uniformly layered, andthe second state being smectic, wherein the orientation of molecules oratoms making up the crystal are oriented in parallel planes or layers.The present inven tion is concerned with the utilization of nematiccholesteric compounds of the type disclosed in the hereinbeforeidentified Eastman Kodak publication.

One suitable cholesteric liquid crystal for use in the present inventionis Eastman Kodaks No. H643 nematic mixture having the followingenumerated properties:

Temperature Range: l5-97C.

Rise Time: 10 milliseconds Decay Time: 350 milliseconds Response Time: 8milliseconds Resistivity: 6.67 x 10 Ohm-cm.

Threshold Voltage: 4 Volts Optimum Voltage: 40 DC; 50-60 A.C.

Contrast Ratio: 100 to l Transmittance, Clear State: 78 percentTransmittance, Saturated State: 0.1%

Excitation Source: 200 volts, peak to peak Measurements Made: 0.5 X 0.5cm. cell nesa coated glass with a 0.5 mil. teflon spacer, in excess of5,000 continuous A.C. hours.

This specific compound is quite suitable for the present inventionparticularly for its clear (uncharged) to opaque (charged) lighttransmission characteristics set forth above. Of course, the particularliquid crystal used could be of the opposite charged variety, or clearwhen charged, turning opaque when uncharged. In the present embodiment,the clear (uncharged) to opaque (charged) variety is desirable so thattransfer directly to xerography printout means may be used without needof white-n-black light reversal. Additionally, it is rather easy withinthe present state of the art of liquid crystals to reduce the decay timefrom 350 milliseconds as in the above compound to 50 milliseconds orless, for even higher speed operations.

Returning now to a further discussion of FIG. 2, specific alphanumericliquid crystal bits 26 are electrically charged to form the individualcharacter programmed and received from bundle 28. A steady orintermittent light source 20 shines through matrix 16, properly chargedto form the letter T for example as hereinbefore set forth, so thatindividual strands 34 of a fiber 0ptics bundle 36 collect the imagerearwardly of matrix 16. Of course, in this case, there are 35 fiberoptic lines 34 provided, one for each liquid crystal bit 26. Althoughbundle 36 is identified as a fiber optics bundle, obviously it could bea projection lens to easily serve the purpose of conveying the characterimage to be printed. to the xerographic printer 24. in any event, theformed character is optically conveyed to the selenium drum of thexerographic printer, which is plus charged in the usual manner asindicated. Other standard components shown of the xerographic printer 24include a charging potential 40, printing resin pickup tray and contents42, heater 44, and a paper supply roll 46 conveying an endless printingpaper supply beneath drum 33 for printout of the electro-opticallyconveyed character.

The immediately preceeding discussion concerned the entire process ofimage forming, conveying and printing of but a single character;obviously, an entire line of such individual alphanumeric characterswill be sequentially activated from the ring counter 14 in order toprint a complete line, in the present embodiment. Once a complete linehas been projected, the selenium drum 38 is advanced by a signal fromthe input 10 to prepare drum 30 to receive another line of characters.Alternatively, the drum could also be advanced at a predetermined rate,with transmission of a signal at the time of each advance to input 10 toactivate display of the next character line in the matrices 16.

instead of a row of individual liquid crystal matrices ilti being usedto form each character individually, matrix 16 may be in the form ofasingle complete line matrix d8, as partially shown in FlG. 3, comprisingany de' sired number of vertical columns of seven liquid crystal bits 26each, so that differential spacing of alphanumeric characters to formeven line printout may be accomplished. Thus, the matrix switching unit14 will be arranged to program an entire alphanumeric liquid crystalmatrix line 43 with all characters in the line displayed simultaneously,rather than equentially as in the case of an individual alphanumericmatrix 16. Similarly, several lines 48 may be provided to be actuatedsimultaneously to even further speed up the printout process.

The precise shape of each alphanumeric bit 26 or 32 is not crucial; theindividual bit may be square as shown, circular or bar shaped, all threevarieties being popular in alphanumeric character displays.

Turning now to FlGS. 4- and 5, another embodiment of the invention isillustrated wherein each alphanumeric character is formed in two stages,using a circular liquid crystai matrix 50 as a primary data receptorfrom the switching matrix or ring counter 14, and a secondary,alphanumeric character display or block 30 which is optically energizedby suitable light conveying means from circular matrix 50, means 51preferably being an optical fiber bundle comprising 35 strands keyed bynumbers, as illustrated from circular matrix 50 to alphanumericcharacter block 30. The structure of circular liquid crystal matrix 50is best illustrated in the partial cross-section view of FIG. 5. Matrix5t} comprises glass plates 52 and 54 having facing transparentelectrodes 56 and 58 coated thereon respectively in a known manner. Inthis case, the common electrode will be 58, coating the entire surfaceof glass plate 54, and indicated as C in FIG. 41, while the individualtransparent electrodes for each of the alphanumeric bits is formed onglass plate 52, by etching away electrode material to form the contacts56 as shown in FIGS. d and 5. An insulated gasket spacer 6t) separatescommon electrode 58 and each individual electrode 56 while thecholesteric nematic liquid crystal is located therebetween at 62. A lens64 receives light or no light through crystal 62. from light source 66and conveys the optical impulse received to a strand 6% of fiber opticsbundle 51. Thus alphanumeric block 31) receives optical impulses whichare displayed on the face thereof and transmitted to final printout inthe same manner as shown in FIG. 2 and described above. In thisembodiment then, block 30 is essentially a transparent view block ratherthan a liquid crystal matrix as in the embodiment of FIG. 2. The reasonfor forming the matrix in the manner shown in FIG. 4 is for costsavings, since each circular liquid crystal matrix 5b can be rapidly andinexpensively formed by well-known processes. The excitation of eachcrystal in matrix 50 is as before; an impulse is received in one or moreelectrodes 56 to turn crystal 62 from clear to opaque (or opaque toclear) in order to form the desired character by optical transmission toblock 39.

As set forth above, several simultaneously actuated line matrixes 48 maybe provided to speed up the printout process. Additionally, as shown inFIG. '6, several lines 48 may be formed adjacent one another to displayany graphic design desired, such as indicated at 70, by excitation ofthe appropriate liquid crystals in each line.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

l. A solid state electro-optical printing system for composing andprinting an infinite variety of characters and/or designs comprisingmemory bank output means for outputting bit data to be translated andsubsequently printed in preselected character and/or design format,matrix bit encoding means fed from said memory bank output means, matrixswitching means operable by said bit encoding means, non-mechanicalelectro-optical graphic character display means for display ing saidpreselected character and/or design format, activated periodically fromsaid bit encoding means, optical image transfer means associated infixed, immovable relationship with said graphic character display means,said electro-optical display means functioning solely as a light shutterwith said optical image transfer means to form and convey by said lattermeans said preselected character and/or design format, and optical inputprinting means for printing images received from said optical imagetransfer means.

2. The invention as recited in claim 1 wherein said electro-opticalgraphic character display means comprise a plurality of graphiccharacter image blocks, each block comprising a plurality ofelectrically actuated liquid crystals, each liquid crystal beingselectively activated from said bit encoding means.

3. The invention as recited in claim 2 wherein said electro-opticalgraphic character display means comprise means for displayingalphanumeric characters.

4. The invention as recited in claim 2 wherein each said liquid crystalis a cholesteric nematic liquid crystal, substantially optically clearin an undisturbed state, and substantially optically opaque underinfluence of an electrical impulse passing therethrough.

5. The invention as recited in claim 2 wherein each said liquid crystalis a cholesteric nematic liquid crystal, substantially optically opaquein an undisturbed state, and substantially optically clear underinfluence of an electrical impulse passing therethrough.

6. The invention as recited in claim 1 wherein said optical imagetransfer means comprise a bundle of optical fibers.

7. The invention as recited in claim 1 wherein said optical inputprinting means comprise a xerographic printer.

8. The invention as recited in claim 7 wherein said xerographic printermeans further comprise a web supply of paper.

9. The invention as recited in claim 1 wherein said electro-opticalgraphic character display means comprise a circular liquid crystalmatrix, each liquid crystal therein being selectively activated fromsaid bit encod ing means, optical signal transfer means from said liquidcrystal matrix, and graphic character display means activated by saidoptical signal transfer means.

iii. The invention as recited in claim 9 wherein said graphic characterdisplay means comprise means for displaying alphanumeric characters.

ii. The invention as recited in claim 9 wherein each said liquid crystalis a cholesteric nematic liquid crystal substantially opticaily clear inan undisturbed state, and substantiaily optically opaque under influenceof an electricai impulse passing therethrough.

12. The invention as recited in claim 9 wherein each said liquid crystalis a cholesteric nematic liquid crystal substantially optically opaquein an undisturbed state and substantialiy optically clear underinfluence of an electrical signal passing therethrough.

H3. The invention as recited in claim 1 wherein said electro-opticalgraphic character display means comprise a line display capable ofdifferential character spacing display of alphanumeric characters.

i i. The invention as recited in claim 1 wherein said electro-opticaigraphic character display means comprise a multiple line display capableof differential character spacing display of alphanumeric characters.

Eb. The invention as recited in claim 1 wherein said electro-optica!character display means comprise a multiple line display capable ofdisplaying graphic designs.

i a a s s STATES :PA'I ENT OFFICE" CERTIFICATE OF CORRECTION Patent No.3,824,604 Dated A July 16, 1974 Inventofl s) Edward I. Stein I It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 3, line 19 insert a hyphen" after "elect'ro" andbefore "optical".

*Colu'mn 4, line 26 correct the spelling of "preceeding"- to--preceding-.

*coiumh} 4, line 49 change "equentially" to -sequentially--. I

*Colurnn- 5, line 34 change spelling "mat rixes" to -matrices I Signedand sealed this 29th day of October 1974.

(SEAL) Attest:

QMCCOY GIBSON JR. c. MARSHALL DANN, A't-testing Officer Commissioner ofPatents

1. A solid state electro-optical printing system for composing andprinting an infinite variety of characters and/or designs comprisingmemory bank output means for outputting bit data to be translated andsubsequently printed in preselected character and/or design format,matrix bit encoding means fed from said memory bank output means, matrixswitching means operable by said bit encoding means, non-mechanicalelectro-optical graphic character display means for displaying saidpreselected character and/or design format, activated periodically fromsaid bit encoding means, optical image transfer means associated infixed, immovable relationship with said graphic character display means,said electro-optical display means functioning solely as a light shutterwith said optical image transfer means to form and convey by said lattermeans said preselected character and/or design format, and optical inputprinting means for printing images received from said optical imagetransfer means.
 2. The invention as recited in claim 1 wherein saidelectro-optical graphic character display means comprise a plurality ofgraphic character image blocks, each block comprising a plurality ofelectrically actuated liquid crystals, each liquid crystal beingselectively activated from said bit encoding means.
 3. The invention asrecited in claim 2 wherein said electro-optical graphic characterdisplay means comprise means for displaying alphanumeric characters. 4.The invention as recited in claim 2 wherein each said liquid crystal isa cholesteric nematic liquid crystal, substantially optically clear inan undisturbed state, and substantially optically opaque under influenceof an electrical impulse passing therethrough.
 5. The invention asrecited in claim 2 wherein each said liquid crystal is a cholestericnematic liquid crystal, substantially optically opaque in an undisturbedstate, and substantially optically clear under influence of anelectrical impulse passing therethrough.
 6. The invention as recited inclaim 1 wherein said optical image transfer means comprise a bundle ofoptical fibers.
 7. The invention as recited in claim 1 wherein saidoptical input printing means comprise a xerographic printer.
 8. Theinvention as recited in claim 7 wherein said xerographic printer meansfurther comprise a web supply of paper.
 9. The invention as recited inclaim 1 wherein said electro-optical graphic character display meanscomprise a circular liquid crystal matrix, each liquid crystal thereinbeing selectively activated from said bit encoding means, optical signaltransfer means from said liquid crystal matrix, and graphic characterdisplay means activated by said optical signal transfer means.
 10. Theinvention as recited in claim 9 wherein said graphic character displaymeans comprise means for displaying alphanumeric characters.
 11. Theinvention as recited in claim 9 wherein each said liquid crystal is acholesteric nematic liquid crystal substantially optically clear in anundisturbed state, and substantially optically opaque under influence ofan electrical impulsE passing therethrough.
 12. The invention as recitedin claim 9 wherein each said liquid crystal is a cholesteric nematicliquid crystal substantially optically opaque in an undisturbed stateand substantially optically clear under influence of an electricalsignal passing therethrough.
 13. The invention as recited in claim 1wherein said electro-optical graphic character display means comprise aline display capable of differential character spacing display ofalphanumeric characters.
 14. The invention as recited in claim 1 whereinsaid electro-optical graphic character display means comprise a multipleline display capable of differential character spacing display ofalphanumeric characters.
 15. The invention as recited in claim 1 whereinsaid electro-optical character display means comprise a multiple linedisplay capable of displaying graphic designs.